Hitherto, as an automobile seat, there has known an automobile seat in which a seat back is pivotally supported on a seat cushion via a pivot shaft so as to be pivotable forward and rearward relative to the seat cushion, and reclining lock devices are mounted on the pivot shaft, whereby the seat back can be maintained in a forward reclined condition, a rearward reclined condition or an upward standing condition relative to the seat cushion and an angle of the seat back relative to the seat cushion can be adjusted. In the automobile seat, when the reclining lock devices are unlocked and the seat back is pivoted rearward relative to the seat cushion, whereby an occupant can recline the upper half of his/her body against the rearward reclined seat back and then take a comfortable posture.
In the automobile seat, return springs for returning the seat back to an upward standing position relative to the seat cushion are employed. More particularly, as the return springs, there are employed spiral springs which are mounted on both ends of the pivot shaft. However, in order to mount the spiral springs, large installation spaces are required. For this reason, in order to obtain a large effective width of the seat back, torsion bar springs are employed in lieu of the spiral springs requiring the large installation spaces.
The torsion bar springs which act as the return spring means are employed in a rear seat which is to be used in a notchback type vehicle in which bulged portions acting as bearing sections for supporting the rear seat are formed on a vehicle body floor and the seat back is supported to the bulged portions by a pivot shaft (Japanese Patent Application Laid-Open Publication No. Hei. 10-157500).
In the rear seat, the torsion bar springs are arranged in the proximity of the seat back so as to extend parallel to the pivot shaft, with one end portions of the torsion bar springs being abutted against a rear surface of the seat back and with the other end portions of the torsion bar springs being abutted against a spare tyre housing section or the like which is provided on a vehicle body floor.
However, in the rear seat, there is a drawback that it is impossible for the torsion bar springs to effectively urge the seat back to an upward standing position relative to a seat cushion.
It is an object of the present invention to provide an automobile seat in which a seat back is pivotally supported on a seat cushion by a pivot shaft acting as a supporting shaft, so as to be pivotable forward and rearward relative to the seat cushion, an angle of the seat back relative to the seat cushion can be adjusted by reclining lock devices, and the seat back can be effectively urged to a vertically standing position by torsion bar springs.
It is another object of the present invention to provide an automobile seat in which torsion bar springs are provided in such a manner that they are not detached from the automobile seat and do not become bars to essential components about the torsion bar springs.